Often during surgery, tissue may be traumatized or compromised such that it needs to be temporarily supported or isolated during the wound healing period. Materials that may be used as tissue sealants also may be used to temporarily support tissue and to seal leaks from tissue until the tissue heals. Tissue sealants that perform these functions are well known in literature and include a variety of natural and synthetic sealants including fibrin sealants, cyanoacrylate based sealants, and other synthetic sealants and polymerizable macromers.
Various types of previously known apparatus have been developed to deliver fibrin sealants, which are derived from blood-based proteins. For example, U.S. Pat. No. 5,605,541 to Holm describes apparatus and methods for applying two or more components of a fibrin sealant. That patent describes a spray head having a central gas discharge port and coaxially arranged annular ports through which respective components of the fibrin sealant are discharged. The spray head may be prone to clogging if the central gas discharge port is restricted.
U.S. Pat. No. 5,368,563 to Lonneman et al. describes a sprayer assembly having angular connecting channels through which components of a fibrin sealant are discharged to cause mixing. U.S. Pat. No. 5,341,993 to Haber et al. describes a hand held sprayer having a remotely actuated spray tip. Both of the devices described in those patents may not be suitable for spraying viscous fluids, which tend to emerge as streams rather than as fine sprays.
U.S. Pat. No. 4,001,391 to Feinstone et al. describes a method for spraying viscous and buttery fluids using a propellant and a pressurized container. The use of propellants is undesirable in medical applications due to uncertain biocompatibility of these materials.
Applicants further have determined that when attempting to use a propellant to apply materials in a laparoscopic setting, which typically is insufflated with a gas to provide a wider field of view for the clinician, the propellant can result in excessive distension of the tissue surrounding the operative site.
In addition, in the above laparoscopic context, when a sprayer is first introduced into the surgical site, for example, via a trocar tube, the ambient pressure may inadvertently charge the supply reservoirs (if the supply lines of the sprayer are not already pressurized), thereby interfering with proper dispensing of the materials into the supply lines when the clinician attempts to operate the device.
In view of the foregoing, it would be desirable to provide apparatus and methods that enable a tissue coating comprising two or more crosslinkable fluids to be applied in situ as a spray.
It further would be desirable to provide apparatus and methods for spraying polymerizable fluids with reduced risk of clogging of the sprayer.
It also would be desirable to provide apparatus and methods that permit spraying of polymerizable fluids in a laparoscopic environment, but which adjusts the pressure in the cavity to account for the introduction of propellant from the sprayer, thereby avoiding excessive distension of the tissue surrounding the operative site.
It still further would be desirable to provide apparatus and methods that permit spraying of polymerizable fluids in a laparoscopic environment, but which prevent material reservoirs of the sprayer from being inadvertently pressurized by the backflow of insufflation gases through the supply lines.